Libguestfs provides ways to enumerate guest storage (eg. partitions,
LVs, what filesystem is in each LV, etc.). It can also run commands
-in the context of the guest. Also you can access filesystems over FTP.
+in the context of the guest. Also you can access filesystems over
+FUSE.
Libguestfs is a library that can be linked with C and C++ management
-programs (or management programs written in OCaml, Perl, Python, Ruby, Java
-or Haskell). You can also use it from shell scripts or the command line.
+programs (or management programs written in OCaml, Perl, Python, Ruby,
+Java, Haskell or C#). You can also use it from shell scripts or the
+command line.
-Libguestfs was written by Richard W.M. Jones (rjones@redhat.com).
-For discussion please use the fedora-virt mailing list:
+Libguestfs was written by Richard W.M. Jones (rjones@redhat.com) and
+hacked on by lots of other people. For discussion, development,
+patches, etc. please use the mailing list:
- https://www.redhat.com/mailman/listinfo/fedora-virt
+ http://www.redhat.com/mailman/listinfo/libguestfs
+
+
+Home page
+----------------------------------------------------------------------
+
+ http://libguestfs.org/
Requirements
- recent QEMU >= 0.10 with vmchannel support
http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html
-- febootstrap >= 2.0
+- febootstrap >= 2.3
- fakeroot
- squashfs-tools (mksquashfs only)
+- genisoimage / mkisofs
+
+- (Optional) hivex >= 1.2.1 to build Windows Registry support
+
+- (Optional) FUSE to build the FUSE module
+
- (Optional) Augeas (http://augeas.net/)
- perldoc (pod2man, pod2text) to generate the manual pages and
- (Optional) Readline to have nicer command-line editing in guestfish.
-- (Optional) 'reged' program from chntpw to decode Windows registry
- entries (http://home.eunet.no/~pnordahl/ntpasswd/)
+- (Optional) xmllint to validate virt-inspector RELAX NG schema
-- (Optional) OCaml if you want to rebuild the generated files, and
- also to build the OCaml bindings
+- (Optional) OCaml + OCaml library xml-light if you want to rebuild
+ the generated files, and also to build the OCaml bindings
+ (http://tech.motion-twin.com/xmllight.html)
- (Optional) local Fedora mirror
- (Optional) GHC if you want to build the Haskell bindings
+- (Optional) Perl XML::XPath, Sys::Virt modules (for libvirt support
+in virt-inspector).
+
+- (Optional, but highly recommended) perl-libintl for translating perl code.
+
Running ./configure will check you have all the requirements installed
on your machine.
Debian
----------------------------------------------------------------------
-libguestfs should build and run on Debian. At the moment we don't
-provide Debian packages, and because of the appliance it's rather
-complicated to provide a package which could be accepted into the
-Debian repositories. Want to help? Please contact us.
+libguestfs is now built as a package in Debian by Guido Gunther and
+the other Debian libvirt maintainers. See:
+
+http://wiki.debian.org/Teams/DebianLibvirtTeam#Packages
+
+You can build for Debian in two different ways, either building a
+Fedora-based appliance using febootstrap, yum, rpm, fakeroot,
+fakechroot (all packaged in Debian). However the recommended way is
+to build a Debian-based appliance using debootstrap and debirf.
+
+Both ways are supported by the configure script.
qemu
By far the most common problem is with broken or incompatible
qemu releases.
-First of all, you need qemu >= 0.10.4, which contains a vmchannel
-implementation. There are several, conflicting, incompatible things
-called 'vmchannel' which at one time or another have been added or
-proposed for qemu/KVM. The _only_ one we support is this one:
-
- http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html
-
-Secondly, different versions of qemu have problems booting the
-appliance for different reasons. This varies between versions of
-qemu, and Linux distributions which add their own patches.
+Different versions of qemu have problems booting the appliance for
+different reasons. This varies between versions of qemu, and Linux
+distributions which add their own patches.
If you find a problem, you could try using your own qemu built from
source (qemu is very easy to build from source), with a 'qemu
need to make edits to the udev configuration.
+vmchannel
+----------------------------------------------------------------------
+
+Previous versions of libguestfs required something called "vmchannel".
+Vmchannel is a special device given to virtual machines which allows
+them to communicate in some way with the host, often (but not always)
+without using a traditional network device. In reality, there is no
+one thing called "vmchannel". This idea has been reimplemented
+several times under the name vmchannel, and other hypervisors have
+their own incompatible implementation(s) too.
+
+In libguestfs <= 1.0.71, we required a specific vmchannel which is
+properly known as "guestfwd" and has been upstream in qemu since here:
+
+ http://lists.gnu.org/archive/html/qemu-devel/2009-02/msg01042.html
+
+In libguestfs >= 1.0.71 we don't require any vmchannel implementation,
+as long as qemu has been compiled with support for SLIRP (user mode
+networking, or "-net user"), which is almost always the case.
+
+However we still offer the ability to use vmchannel, and in future we
+may add support for other types of qemu, which is useful in a few
+cases, specifically where qemu packagers decide to compile out support
+for SLIRP (qemu packagers: please don't do this).
+
+
+Supermin appliance
+----------------------------------------------------------------------
+
+If you configure with --enable-supermin then we will build a supermin
+appliance (supermin = super-minimized). This is a very specialized
+appliance which is built on-the-fly at runtime (specifically, when you
+call guestfs_launch).
+
+The normal appliance is a self-contained Linux operating system, based
+on the Fedora/RHEL/CentOS Linux distro. So it contains a complete
+copy of all the libraries and programs needed, like kernel, libc,
+bash, coreutils etc etc.
+
+The supermin appliance removes the kernel and all the executable
+libraries and programs from the appliance. That just leaves a
+skeleton of config files and some data files, which is obviously
+massively smaller than the normal appliance. At runtime we rebuild
+the appliance on-the-fly from the libraries and programs on the host
+(eg. pulling in the real /lib/libc.so, the real /bin/bash etc.)
+
+Although this process of rebuilding the appliance each time sounds
+slow, it turns out to be faster than using the prebuilt appliance.
+(Most of the saving comes from not compressing the appliance - it
+transpires that decompressing the appliance is the slowest part of the
+whole boot sequence). On my machine, a new appliance can be built in
+under a fifth of a second, and the boot time is several seconds
+shorter.
+
+The big advantage of the supermin appliance for distributions like
+Fedora is that it gets security fixes automatically from the host, so
+there is no need to rebuild the whole of libguestfs for a security
+update in some underlying library.
+
+There are several DISADVANTAGES:
+
+It won't work at all except in very narrow, controlled cases like the
+Fedora packaging case. We control the dependencies of the libguestfs
+RPM tightly to ensure that the required binaries are actually present
+on the host.
+
+Furthermore there are certain unlikely changes in the packages on the
+host which could break a supermin appliance, eg. an updated library
+which depends on an additional data file.
+
+Also supermin appliances are subjected to changes in the host kernel
+which might break compatibility with qemu -- these are, of course,
+real bugs in any case.
+
+Lastly, supermin appliances really can't be moved between branches of
+distributions (eg. built on Fedora 12 and moved to Fedora 10) because
+they are not self-contained and they rely on certain libraries being
+around. You shouldn't do this anyway.
+
+Use supermin appliances with caution.
+
+
Notes on cross-architecture support
----------------------------------------------------------------------
At the moment we basically don't support cross-architecture or
32-on-64. This limits what is possible for some guests. Filesystem
-operations and FTP export will work fine, but running commands in
-guests may not be possible.
+operations and FUSE will work fine, but running commands in guests may
+not be possible.
To enable this requires work for cross-architecture and 32-on-64
support in febootstrap, fakeroot and fakechroot.
- python
- rpm-python http://www.rpm.org/
- yum http://yum.baseurl.org/
- - febootstrap http://et.redhat.com/~rjones/febootstrap/
+ - febootstrap http://people.redhat.com/~rjones/febootstrap/
Copyright and license information
----------------------------------------------------------------------
-Copyright (C) 2009 Red Hat Inc.
+Copyright (C) 2009-2010 Red Hat Inc.
The library is distributed under the LGPLv2+. The programs are
distributed under the GPLv2+. Please see the files COPYING and